I am anti-copyright, but I think you're considering this through the lens of a computer scientist/rocket engineer instead of someone who's had to work a worthless desk job or wait tables or paint houses.
As someone who recently (and probably unsustainably) got out of the cycle of worthless jobs and knows a handful of musicians, here's my perspective:
Indie (and indie label) musicians can actually do fairly well with recorded music. No, they won't be rich. Middle class is at most the target, usually under. Live in a third-tier city and have few expenses. You don't need to sell very much for a baseline livable state.
$10000 a month isn't an achievable target for most working artists. $800, on the other hand, is, even without touring. Sell a handful of Bandcamp copies, sell a few physical copies (cassettes are best for this in the current moment, being cheap to produce and having a fairly loyal audience), have your back catalog do well enough on streaming.
$800 is enough to live on, if you're living with roommates. In many ways, living with $800/month and no unfulfilling 40hr job is much better than living with $1800 and an unfulfilling 40hr job. Even if you don't want to live with roommates, it cuts the amount of work for an employer you have to do by a great deal. Working low-skill work is soul-crushing.
For authors, from what I understand, this baseline is even more achievable. If you have no hopes of getting rich, the current copyright system is fine.